Answer: intangible

AnswerCrossword Clue
INTANGIBLEHard to describe
INTANGIBLEDifficult to grasp
intangibleDifficult or impossible to define or understand; vague and abstract
intangibleUnable to be touched or grasped; not having physical presence
intangiblethat cannot be touched also UNTANGIBLE / something that cannot be touched
intangible(of an asset or benefit) Not constituting or represented by a physical object and of a value not precisely measurable